Batteries are being used in many different applications, such as electric vehicles. However, batteries often have limitations based on size, capacity, cost, etc. that limit usefulness and popularity. For example, electric vehicles have distance limitations based on battery capacity that may be unacceptable to consumers. In addition, electric vehicles often require batteries to be replaced at a large cost on a time interval that may make electric vehicles an expensive alternative to fossil fuel powered vehicles. Increasing battery capacity and useful life helps to increase popularity of electric vehicles and other battery powered devices.
While controlling battery charging and discharging, often control loops have limits that are not known to the battery controller. The limits may be a minimum voltage, a maximum charge or discharge rate, a maximum state-of-charge, and the like. However, when the battery controller seeks to respond to a change in load, a quick charge condition, etc., the battery controller will produce a control signal that may take the battery to a limit where constraints may then take over to ensure that battery does not exceed the limit. Often, the nonlinearities imposed by the constraints cause instability, which may have an undesirable effect.